[Cluster-devel] [PATCH] gfs2: Special-case rindex for gfs2_grow

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> To speed up the common case of appending to a file,
> gfs2_write_alloc_required presumes that writing beyond the end of a file
> will always require additional blocks to be allocated.  This assumption
> is incorrect for preallocates files, but there are no negative
> consequences as long as *some* space is still left on the filesystem.
> 
> One special file that always has some space preallocated beyond the end
> of the file is the rindex: when growing a filesystem, gfs2_grow adds one
> or more new resource groups and appends records describing those
> resource groups to the rindex; the preallocated space ensures that this
> is always possible.
> 
> However, when a filesystem is completely full, gfs2_write_alloc_required
> will indicate that an additional allocation is required, and appending
> the next record to the rindex will fail even though space for that
> record has already been preallocated.  To fix that, skip the incorrect
> optimization in gfs2_write_alloc_required, but for the rindex only.
> Other writes to preallocated space beyond the end of the file are still
> allowed to fail on completely full filesystems.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Hi,

ACK. Yeah, we need this.

Bob Peterson